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MC Industrial Completes Project to Help Ameren Missouri Cut Emissions at Sioux Energy Center
MC Industrial, Inc., an independent McCarthy Company, has completed a $200 million project for Ameren Missouri, as part of a more than $600 million installation of a scrubber system that 
significantly reduces sulfur dioxide emissions at the Ameren Missouri Sioux Energy Center plant in West Alton, Mo. The project helps Ameren Missouri comply with federal environmental regulations requiring major reductions in sulfur dioxide emissions and also helps the plant reduce its mercury emissions.
MC Industrial served as both general contractor and construction manager overseeing the installation of two wet flue gas desulphurization (WFGD) scrubber systems –a sophisticated system that removes more than 95 percent of the plant’s sulfur dioxide emissions. At the peak of construction, the project employed more than 550 people and achieved a project safety incident rate well below the national average incident rate for industrial projects.
MC Industrial managed more than 2.2 million hours and $100 million of payroll for a variety of local and national trade contractors on the new facility. MC Industrial self-performed foundation construction, structural steel erection, duct assembly, erection and equipment setting for the project. The project included installation of 23,000 cubic yards of concrete; 7,000 pieces of structural steel weighing a total of 2,400 tons; 1,800 tons of ductwork; 70,000 linear feet of piping systems; 265 miles of electrical wire, ten 55,000 gallon-per-minute recycle pumps; and four 14,500 horsepower axial type fans; in addition to the two scrubber systems.
These were the first wet scrubbers that MC Industrial has installed for Ameren Missouri, said MC Industrial President, Tom Felton, and he said the project completed about a month ahead of final schedule. “We also achieved excellent quality and safety, maintained budget reporting and provided monthly cash flow estimates for Ameren Missouri,” said Felton. “The project has been a great success and the ability and willingness of the on-site team to get involved in the operation and merge with the Ameren Missouri team has been great.”
Sioux Energy Center, completed in 1968, is a two-unit, 986-megawatt coal-fired generating plant. Construction of the scrubbers began in 2006, but the project was slowed during the nation’s 2008/2009 financial market crisis, and was completed in November 2010. Each generating unit has its own scrubber. As hot flue gas passes through each scrubber, slurry of crushed limestone and water is sprayed through it. The limestone in the slurry reacts with sulfur in the flue gas, creating synthetic gypsum, an inert material that will be captured and stored in a new landfill on plant property. Gypsum is the main component of wallboard.
A critical stage of the project included replacing the inlet ductwork for the two existing electrostatic precipitators (ESP) and connecting the new WFGD scrubber units to the operating plant during a scheduled plant outage. Each of the two ESP inlet ducts were assembled and insulated prior to the scheduled outage and set as a single 270,000-pound piece or 130 tons section of ductwork. For the second unit’s outage, a Manitowoc 888 crane in a ringer configuration (with 1.3 million pounds of counterweight) and a 300-foot boom were mobilized to handle the removal and replacement of the duct. MC Industrial and the project team developed extensive execution and lifting plans for both of the outages. The advanced planning included the utilization of Building Information Management (BIM) modeling and animation systems to assure the execution and lift plans would be successful. The replacement of the two units’ ESP ducts was the critical path of the outage schedule and completed without incident ahead of the planned completion dates.
“Most construction occurred within an operating plant and was managed under extreme space constraints,” said MC Industrial Project Director Chris Marcon. “The project team’s planning efforts required constant coordination and communication with plant operators to ensure that construction activities did not interfere with plant operations. The coordination efforts included extensive and regular use of BIM tools.”